Can I move a virtualenv?

问题:

This question is not a duplicate.

It pertains not just to renaming a virtual environment, but to actually moving it to a different directory, including, potentially, a different user's directory.

This is not the same as merely renaming a virtual environment, especially to people unfamiliar with virtualenvs.

If I create a virtualenv, and I move it to a different folder, will it still work?

$ virtualenv -p /usr/bin/python3 /home/me/Env/my-python-venv
$ source Env/my-python-venv/bin/activate
(my-python-venv) $ 

...later that day, the virtual environment MOVED...

(my-python-venv) $ deactivate
$ mkdir -p /home/me/PeskyPartyPEnvs
$ mv /home/me/Env/my-python-venv /home/me/PeskyPartyPEnvs/

Question:

Will this work?

$ source /home/me/PeskyPartyPEnvs/my-python-venv/bin/activate
(my-python-venv) $ /home/me/PeskyPartyPEnvs/my-python-venv/bin/pip3 install foaas

I mean this as less of a question about the wisdom of trying this (unless that wisdom is humorous, of course), and more about whether it's possible. I really want to know whether it's possible to do in Python 3, or whether I just have to suck it up and clone it.

Can I just mv a virtualenv like that without sadness? I do want to avoid sadness.

回答1:

Yes. It is possible to move it on the same platform. You can use --relocatable on an existing environment.

From --help:

--relocatable -- Make an EXISTING virtualenv environment relocatable. This fixes up scripts and makes all .pth files relative.

HOWEVER, this does NOT seem to change the activate script, and rather only changes the pip* and easy_install* scripts. In the activate script, the $VIRTUAL_ENV environment variable hardcoded as the original /path/to/original/venv. The $VIRTUAL_ENV variable is used to set the PATH of your active environment too, so it must be changed based on the new location in order to call python and pip etc. without absolute path.

To fix this issue, you can change the $VIRTUAL_ENV environment variable in the activate script (for example using sed), and everything should be good to go.

An example of usage:

$ cd ~/first
$ virtualenv my-venv
$ grep 'VIRTUAL_ENV=' my-venv/bin/activate
VIRTUAL_ENV="/home/username/first/my-venv"
$ virtualenv --relocatable my-venv
Making script my-venv/bin/easy_install relative
Making script my-venv/bin/easy_install-2.7 relative
Making script my-venv/bin/pip relative
Making script my-venv/bin/pip2 relative
Making script my-venv/bin/pip2.7 relative
### Note that `activate` has not been touched
$ mkdir ~/second
$ mv my-venv ~/second
$ cd ~/second
$ grep 'VIRTUAL_ENV=' my-venv/bin/activate
VIRTUAL_ENV=/home/username/first/my-venv
### (This variable hasn't been changed, it still refers to the old, now non-existent directory!)
$ sed -i -e 's|username/first|username/second|' my-venv/bin/activate
## sed can be used to change the path.
## Note that the `-i` (in place) flag won't work on all machines. 
$ source my-venv/bin/activate 
(my-venv) $ pip install foass
...
(my-venv) $ python 
[...]
> import foass

Hooray, now you can install things and load them into your newly located virtual environment.

回答2:

The --relocatable argument to virtualenv appears to allow you to do this.

回答3:

Yes, this should be possible if you haven't done anything that depends on the current directory of the virtualenv.

However, if you have the choice, the best thing to do is to create new virtualenv and start using the new virtualenv instead. This is the safest choice and least likely to cause issues later.

The documentation does mention that:

Each virtualenv has path information hard-coded into it,

For example, if you have run setvirtualenvproject then it won't be able to switch to the right directory after you run workon ... so in that case you'd need to fix that manually.

In general a virtualenv is little more than a directory with the necessary Python interpreter files plus packages that you need.

回答4:

BUT ALAS:

No, you can't simply mv. There are workarounds, but it might be easier to reinstall.

(my-python-venv)$ /home/me/PeskyPartyPEnvs/pip3 install foaas
zsh: /home/me/PeskyPartyPEnvs/pip3: bad interpreter: /home/me/Env/my-python-venv/bin/python3: no such file or directory
(my-python-venv)$ deactivate
$ 

... presses enter a lot in frustration, and the following works

$
$
$ pip3 search foaas

Except it is not from my-python-venv, ergo sadness.

Want to mv your virtualenv and use it, otherwise unmodified?

Short Answer:

Well, ya can't.

回答5:

Using answers of this and other threads about similar topic, I've made a bash script that, located and executed within the virtualenv directory itself, will help with your virtualenv moves.

After doing virtualenv --relocatable yourenv you'll need to change your VIRTUAL_ENV variable every time you move the directory, so if you don't wan't to change it manually, use this.

#!/bin/bash \n 
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
EXISTING=$(grep 'VIRTUAL_ENV=' bin/activate)  
NEWDIR=VIRTUAL_ENV=\"$DIR\"
sed -i -e "s|$EXISTING|$NEWDIR|" bin/activate
source bin/activate

I hope it helps.

回答6:

For Python 3.3+ (with new venv built-in module)

Short Answer (regardless of version):

• Just recreate, it's easy!!
• It's difficult to move/rename virtual environments...

---

Long Answer:

As of Python v3.3, virtualenv has become a built-in module named venv.

The --relocatable option mentioned in other answers has not been included in venv, and currently there is no good, safe way that I'm aware of to either rename or relocate a Python virtual environment.

However, there is a fairly simple way to simply recreate a virtual environment, with all its current installed packages. See this answer about renaming a virtual environment. During the process you can recreate the new environment in whatever location and with whatever name you desire.

In that answer, he does mention a few other 3rd party packages which may support direct renames or moves. If you are settled on pursuing a way to move a virtual environment intact, you could look into if those work with venv as well.

Note: In that answer, it is focused on virtualenv, rather than venv. See the next section for how to translate.

---

venv vs. older virtualenv command syntax

The command to use venv is:

python -m venv

rather than just virtualenv, which installs as a command in the original package. Where "python" refers to however you run your python executable, which could be a variety of things, such as:

1. python
2. py or py -3.7 or similar (the Python Launcher for Python 3.3+)
3. python3 (typically needed for linux environments that dual install python 2 and 3